The present application relates to a back-end-of-the-line (BEOL) metal-insulator-metal (MIM) capacitor and a method of forming the same. More particularly, the present application relates to a BEOL MIM capacitor that includes three electrode plates in which the first electrode plate of the MIM capacitor is an electrically conductive structure embedded in an interconnect dielectric material layer of a lower interconnect level.
On-chip capacitors including metal-insulator-metal (MIM) capacitors are essential for many semiconductor chips. For example, MIM capacitors are frequently utilized as decoupling capacitors for mitigating power supply or switching noise caused by changes in current flowing in an integrated chip. MIM capacitors are often integrated into a back-end-of-the-line (BEOL) metallization stack, at a position between an underlying first metallization layer and an overlying second metallization layer. When integrated, a MIM capacitor is commonly formed as a stacked structure including at least two planar electrode plates or three planar electrode plates. The various electrode plates in prior art BEOL MIM capacitors are generally embedded in an interconnect dielectric material layer that constitutes one of the interconnect levels of a multilevel interconnect structure. BEOL MIM capacitors that contain three planar electrode plates have better performance than BEOL MIM capacitors that contain two planar electrode plates.
Despite providing improved performance, BEOL MIM capacitors that contain three planar electrode plates are formed utilized complex processes in which topography related challenges are of one concern. Also, and when etching metal/high-k capacitor dielectric stacks, there is a challenge to control the contact via profile. There is thus a need to provide a BEOL MIM capacitor that contains three planar electrode plates utilizing a simplified method that reduces the topography related challenges and other problems that exist utilizing prior art methods of forming BEOL MIM capacitors that contain three planar electrode plates.